Disputer

A disputer is an actor who monitors sequencers in optimistic rollups or relayers in optimistic bridges to check for fraudulent or erroneous actions during the challenge period. If a disputer identifies a suspicious transaction withinthis timeframe, they submit a fraud proof—evidence indicating that the transaction may be invalid—to the settlement layer, which has the ultimate authority to judge the validity of transactions based on the evidence provided. This role is crucial for safeguarding the integrity of optimistic transaction systems, where transactions are approved by default without scrutiny at the Layer 1 level.

Disputers are financially incentivized to identify invalid transactions, as they are rewarded if their claim is substantiated.